Boiler



March 6, 1934. A, U, WETHERBEE 1,950,043

BOILER Filed Aug. 4, 1952 5 sheets-sheet 1 March 6, 1934. A U WETHERBEE1,950,043

BOILER Filed Aug. 4, 1932 5 Sheets-Sheet 2 9 J d /7 a C a ,aff/f: w::QQ/N

WSA

March 6, 1934. A. u. WETHERBEE 1,950,043

BOILER Filed Aug. 4, 19252 5 Sheets-Sheet 4.

March 6, 1934. A u. WETHERBEE BOILER Filed Aug. 4, 1932 5 Sheets-Shea?I5 Patented Mar.' 6, 1934 UNITED STATES PATENT OFFICE 12 Claims.

This invention relates to boilers,'and more particularly to boilersemploying a plurality of drums connected in a ring circuit.

I have illustrated my invention, by way of example, as applied to aboiler comprising three drums connected in a ring circuit. Though myinvention is particularly adapted for a three drum boiler, it may beapplied, in its broader aspects, to boilers using more than three drumsas will be understood'by those skilled in the art, and I do not,therefore, limit my invention to three drum boilers only.

The primary object of my invention is to provide a boiler ofcomparatively simple and inexpensive construction which possesses highefficiency. More specifically, the main object of my invention is theprovision of a boiler having a large heat absorbing area and'rapidcirculation, to the end of high heat absorbing capacity. Further objectsand advantages of my invention will appear from the detail description.

In the drawingsz- Figure 1 is a vertical central sectional view of aboiler constructed in accordance with my invention as applied, takenfrom front to back of the casing, with parts in elevation;

Figure 2 is a view similar to Figure 1, showing a modified form of myinvention;

Figure 3 is a view similar to Figure 1, showing a second modified formof my invention;

Figure 4 is a view similar to Figure 1, showing a third modified form ofmy invention;

Figure 5 is a view similar to Figure 1, showing a fourth modified formof my invention;

Figure 6 is a section taken substantially on line 8 6 of Figure 1.

In Figure 1 of the drawings Ihave illustrated my boiler as mounted in acasing which is reenforced by a frame 2 formed of structural steel. Theframe and the casing are, in general, of known construction and need notbe illustrated nor described in detail. The casing includes a furnace 3at the rear of which is a back wall 4, the space 5 above the grate 6constituting the combus- 45 tion space of the furnace.

The boiler is mounted in casing l at the upper portion thereof. 4Frame 2comprises two main side supporting beams 7 of I cross section. Theboiler comprises an upper steam and water drum 5c 8 disposed adjacentthe back wall of the casing, a. lower mud drum 9 also disposed adjacentthe back wall of the casing, and a water drum 10 disposed between drums8 and 9 and at the front wall of the casing. These drums are connectedte together in a ring circuit by banks of tubes 11,

12 and 13. 'I'he tubes are bent and enter the drums radially thereof, ina manner well known in the art. Drum 8 is provided with a steam nozzle14. This drum may also be provided with a dry pipe, suitable battlesadjacent to the dry pipe, and a feed water pipe extending along the drum8 at the lower portion thereof for supplying feed water to the drum in aknown manner; all known in the art. The tubes 11 constitute thedowncomers, certain tubes conducting more feed water than other tubes,the tubes 12 constitute the upgoers for the upward fiow of steam andwater therethrough at relatively high speed, and the bank of tubes 13also constitute upflow tubes for conducting the steam and water fromdrum l0 to drum 8 in which the steam is liberated.

The water drum 10 is anchored to the under faces of beams 7 in asuitable manner, as by means of brackets 15 suitably secured to the.heads of the drum, these brackets being riveted or otherwise suitablysecured to beams 7. Drum 8 is slidably mounted, at each end and in asuitable manner, upon the upper faces of beams 7.

An arch 16 ext-ends over the upper portion of the drum 8 and is providedwith an opening to 80 accommodate the nozzle y14, this opening being ofappreciably greater extent than the nozzle to permit the slidingmovement of drum 8 referred to. The top of the casing is closed by asuitable roof structure 17.

A baffle 18 formed of slabs or tiles of suitable refractory material, issupported upon the upper tubes of the bank of tubes 12 and extends up'-Wardly from the mud drum 9 for approximately one-half the length of thetubes. An upper baie 19 extends across the bank of tubes 13 from thelower row of tubes thereof to the next to the top row of tubes, thisbale being inclined upwardly and forwardly of the casing. An angle bar20 is secured to the lower row of tubes of the bank 13 by U-bolts 21,vor in any other suitable man ner. The vertical flange of this bar fitsinto a groove 22 formed in the upper edge of a vertical y baie 23, thelower edge of which is rabbeted and seats upon the upper edge of baiiie18. The up- 10c per edge of baiiie 23 is disposed closely adjacent thelower edge of bailie 19, so as to form a closure therewith. Groove 22 isof appreciably greater width and depth than the vertical ange or arm ofbar 20 thus permitting movement of bae 23 105 relative to the bar. Thisis of importance as permitting movement of baiiie 23 in accordance withexpansion and contraction of the bane 18 and tubes l2, While alsopermitting relative move= ment between this baiie and the heme l@ andtubes 13. In this manner I avoid subjecting the bailie 23 to stressessuch as would tend quickly to destroy the baffle. I also provide simpleand efficient means for normally holding the baiiie 23 in position whilepermitting ready removal and replacement thereof as required. Thisbaffle may be constructed of slabs or tiles of proper width fitted endto end across the casing to form a suitable barrier or baffle, as isknown in the art in the constructionof baffles and similar structures.

The casing further comprises a fire wall 25 disposed adjacent the backof the casing. An arch 26 is disposed between the-back wall and the iirewall and a series o f tubes, one of which is shown at 27, extend throughthis arch, these tubes connecting the mud drum 9 to a. header 28 at thetop of front wall 29 of the furnace. A series of tubes 30 connect header28 to water drum 10, the header 28 being at a lower level than the waterdrum and the tubes 30 being inclined upwardly and rearwardly of thecasing. The tubes 30 alternate with the tubes 27 and provide asupporting structure for the roof 31 of the furnace, the furnace roofbeing thus water cooled. The tubes 27 form a slag screen which extendsabove the fire box in the furnace.

A baille 32 extends from the arch structure 26 upwardly and forwardly ofthe casing to within a short distance of water drum 10. A baille 33extends downwardly from the drum 8 between certain of the tubes 11. Thisbaffle 33 is suitably secured to certain of the tubes 11 by U-bolts 34or in any other suitable manner. 'I'he hot products of combustion are-thus caused to pass downwardly along the tubes 11 and across the lowerportion of these tubes and then upwardly along the remaining tubes 11 tothe'chimney or outlet,` opening 24, this opening being controlled by asuitable valve or damper 24a.

The hot products of combustion from the furnace flow rearwardly and thenupwardly along and across the lower bank of tubes and are then deflectedby the baffle 19 forwardly of the casing across the tubes 13, thesegases then passing through the space between baffle 19 and roof 17 andiiowing downwardly acrossl tubes 13 in a reverse direction, after whichthe gases flow across and along the tubes 11 and-thence to the chimneyopening or outlet 24 of the furnace.

Mud drum 9 extends into a recess at the upper edge of fire wall 25, thespace between this wall and the drum being sealed by a packing 35 ofsuitable material, such as asbestos. The ends of this drum may extendthrough suitable openings in the sides of the casing, as may the ends ofdrum 8. In such case packing rings of suitable refractory material maybedisposed about the ends of the drums to provide closures between thesame and the casing walls. Preferably, asbestos in a highly fibrouscondition is employed for effecting these closures, though any othersuitable material which possesses sufllcient resiliency to permit of thedesired movement of drums 8 and 9 may be used.

The tubesl 27 and 30 and the header 28 are included in the circulatingsystem of the boiler and the drum 8 is mounted for sliding movement onthe beams 7 of the frame, mud drum 9 being tube suspended and free formovement to accommodate expansion and contraction of the tubes, asstated.

It is particularly pointed out that in the boiler constructionillustrated, water drum 10 is anchored to the undersides of beam 7 andthe water and steam drum 8 is slidably mounted upon the upper sides ofthese beams, the mud drum 9 being tube suspended from the drums 8 and 10and being free for movement to accommodate expansion and contraction ofthe tubes 11 and 12. This provides a simple but highly efficientconstruction of boiler in which both the water drum and the water andsteam drum are effectively supported in such manner as to prevent anytendency toward tipping of the boiler structure while permittingexpansion and contraction of the tubes 13, dueto the sliding movement ofdrum 8, as well as the tubes 11 and 12. In this manner I eliminateundesirable stresses due to expansion and contraction of the tubes, suchas would be apt to cause injury to either the tubes or the drums if thedrum 8 were not mounted for sliding movement and the mud drum 9 were notcapable of movement to accommodate expansion and contraction of tubes 11and 12.

In Figure 2 I have illustrated my lboiler as used with a furnaceemploying gas, oil or pulverized coal as fuel, and the construction ofthe casing 36 is modified accordingly. A header 37 extends across theback of the furnace and is connected by tubes 38 to mud drum 9. Tubes 38alternate with tubes 39 which connect the header to drum 10 and areinclined at an inclination upwardly -and forwardly of the casing, thesetubes 39 extending over the combustion space of the furnace andconstituting a slag screen. A wall 40 extends across the casing adjacentand in front of mud drum 9, and a baille 41, which rests upon the lowerportions of tubes 39 and constitutes a fire arch, extends from wall 40to theback wall of the casing. Tubes 12a, disposed in a row above thebank of tubes 13 and adjacent roof 17a, connect drum 10 to drum 9 andsupport roof 17a. With the exceptions noted, the boiler of Figure 2 is,in general, similar to that of Figure 1.

In the modified form of Figure 3, tubes 38a alternatel with tubes 39,and connect the mud drum 9 to header 37. In addition, I provide tubes42, which may correspond in number to tubes 38a and connect the mud drumto header 37 at the top thereof. A wall 43 extends across the casingadjacent and in front of drum 9, there being a baille member 44supported upon tubes 38a and 39, which baiiie member extends upwardlyabout the front face of wall 43 with the inner ends of tubes 38a beingcurved upwardly about the front end of this baffle. The tubes 38a and 42provide, with drum 9 and header 37, a local circuit effective forheating theV water in the mud drum.

The boiler shown in Figure 4 is the same as that of Figure 2, exceptthat alternate tubes 12b of the bottom row of the lower bank of tubesare bent downwardly so as to provide an upper and supplemental slagscreen. If desired, and under certain conditions, header 37 and tubes 38and 39 may be omitted.

The modified form illustrated in Figure 5 may be considered as acombination of the forms shown in Figures 1 and 3. In this form, tubes39a connect back header 37a to front header 28a tubes 38h, whichalternate with tubes 39a, connect header 37a to drum 9, and tubes 42aconnect mud drum 9 to header 37a and serve a:

downcomers.

In all of the forms of my boiler illustrated, thu slag screen extendsover the combustion space o the furnace. The tubes of this screenmaterial ly increase the surface area exposed to the ho gases ofcombustion, which increases the hea absorbing capacity of the boiler,resulting in in creased efliciency. They also facilitate the obtainingof long ame travel, which is desirable.

In the construction of boiler in Figures 1 to 5, inclusive, the steamand water drum 8 is of appreciably greater diameter than the mud drum 9,and the mud drum and the water drum are of substantially the sameldiameter. It is the present practice in boiler construction to have theupper water and steam drum of the same diameter as the mud drum. I havefound, however, that by increasing the diameter of the steam and waterdrum I obtain certain important advantages over the present practice. Inpractice, I prefer to have the water and steam drum approximatelyone-third greater in diameter than the mud drum 9. This relatively greatdiameter of the steam and water drum has numerous advantages. Itprovides greater water and steam storage space than heretofore, and alsoprovides an increased steam liberating area avoiding splashing in thesteam and water drum. Another important advantage of employing the steamand water drum of relatively great diameter is that it provides greaterwater endurance surface than is available in boilers constructed inaccprdance with the present practice, maintaining the water more nearlyat a constant level. This is an important consideration in the operationof boilers. Also, with a large drum the tubes are less liable to beuncovered due to variations in water level. By water endurance surface Irefer to the net area of the actual contact surface between the waterand the steam space in the boiler, which serves as the measure of theability of a boiler to deliver steam without dropping its water level ifboiler feeding is stopped.

In the several forms of myinvention illustrated the setting or casing,including the furnace, has been illustrated as of more or lessconventional construction. It will be understood, however, that theconstruction of the setting or casing may be varied within wide limitswithout departing from my invention which resides primarily in theconstruction and arrangement of the boiler drums and tubes andassociated parts. The mud drum 9 is provided with a blow-off pipe 45 forblowing mud and sediment out of this drum in a known manner.

As above indicated and as will be understood by those skilled in theart, changes in construction and arrangement of parts of my inventionmay be resorted to without departing from the eld and scope of the same,and I intend to include all such variations, as fall within the scope ofthe appended claims, in this application in which the preferred formsonly of my invention are disclosed.`

This application is a continuation in part of my copending applicationfor Three drum boiler, Serial No. 342,506, filed February 25, 1929.

What I claim iszl. In combination, a casing comprising a furnaceprovided with a roof and extending forwardly from the front wall of thecasing and opening into the same, an upper steam and water drum adjacentthe rear of the casing, a water drum adjacent the front of the casingand below the steam and water drum, a lower mud drum, banks of tubesconnecting the drums in a ring circuit, a header adjacent the front wallof the furnace, tubes connecting the header to the water drum andsupporting the roof of the furnace, and tubes connecting the header tothe mud drum and extending over the combustion space of the furnace.

2. In combination, a casing comprising a furnace provided with a roof,an upper steam and water drum adjacent the rear of the casing, a waterdrum adjacent the front of the casing and below the steam and waterdrum, a lower mud drum, banks of tubes connecting the drums in a ringcircuit, a header adjacent the front wall of the casing,- tubesconnecting the header to the water drum and supporting the roof of thefurnace, and tubes connecting the header to the mud drum and extendingover the combustion space of the furnace.

3. In combination, a casing comprising a furnace extending forwardlyfrom the front wall of the casing and opening into the same, an uppersteam and water drum adjacent the rear of the casing, a drum adjacentthe front of the casing and below the steam and water drum, a lower muddrum, bank of tubes connecting the drums, a header adjacent the frontwall of the furnace, tubes connecting the header to the water drum, andtubes connecting the mud drum to the header and extending over thecombustion space of the furnace.

4. In combination, a casing comprising a furnace, an upper steam andwater drum adjacent one end of the casing, two lower drums one of whichis a mud drum and the other of which is la water drum, the water drumbeing disposed between the mud drum and the steam and water drum andadjacent the other end of the casing, the mud drum being disposedadjacent the first mentioned end of the casing, banks of tubesconnecting the drums, a header at one end of the casing, tubesconnecting the header to one of the lower drums, and tubes connectingthe header to the other lower drum and extending over the furnace, thelast mentioned tubes being disposed below the lower of said banks oftubes a distance greater than the vertical distance between adjacenttubes of said lower bank and providing a slag screen over the furnace.

5. In combination, a casing comprising a furnace, an upper steam andwater drum adjacent one end of the casing, two lower drums one of whichis a mud drum and the other of which is a water drum, the water drumbeing disposed between the mud drum and the steam and water drum andadjacent the other end of the casing, the mud drum being disposedadjacent the rst mentioned end of the casing, banks of tubes connectingthe drums, a header at one end of the casing and adjacent one of saidlower drums, tubes connecting the header to .the lower drum adjacentthereto and extending over the furnace, and tubes connecting the headerto the other lower drum and extending over the furnace, the lastmentioned tubes being disposed below the lower of said banks of tubes adistance greater than the vertical distance between adjacent tubes ofsaid lowerbank and providing a slag screen over the furnace.

6. In combination, a casing comprising a furnace, two drums disposed onebelow the other and adjacent an end of the casing, a third drum adjacentthe other end of the casing, banks of tubes connecting the drums, aheader at the jacent the other end of the casing,

nace, an upper steam and water drum adjacent the rear of the casing, adrum adjacent the front of the casing and below the steam and waterdrum, a lower mud drum, banks of tubes connecting the drums in a ringcircuit, a header adjacent the back wall of the casing, tubes connectingthe header to the mud drum and extending over the combustion space ofthe furnace. and tubes connecting the header to the water drum andextending over the combustion space of the furnace.

8. In combination, a casing comprising a furnace, an upper steam andwater drum adjacent the rear of the casing, a water drum adjacent thefront of the casing and below the steam and water drum, a lower muddrum, banks of tubes connecting the drums in a ring circuit, a headeradjacent the back wall of the casing, tubes connecting the header to thewater drum and extending over the combustion space of the furnace, afirst series of tubes connecting the mud drum to the header, and asecond series of tubes connecting the header to the mud drum, the twosaid series of tubes and the header and the mud drum formv ingv a localflow circuit. 9. In combination, ahcasing comprising a furnace, twodrums disposed one below the other and adjacent an end of the casing, athird drum adbanks of tubes connecting the drums, a header at the firstmentioned end of the casing, tubes connecting the header to said thirddrum and extending over the combustion space of the furnace, a lowerseries of tubes alternating with the tubes extending over the combustionspace and connecting the header to the lower one of said two drums, andan upper series of tubes connecting the header to said lower drum.

10. In combination, a casingcomprising a furnace, two drums disposed onebelow the other and adjacent an end wall of the casing, a third drumadjacent the other end of the casing, banks oftubes connecting thedrums, a header at the first mentioned end of the casing, a wall withinand extending across the casing adjacent the lower one of said twodrums, tubes connecting the header to said lower drum, tubes connectingthe header to said third drum and extending over the combustion space ofthe furnace, and a baffle member extending between said wall and theadjacent end wall of the casing, said member being supported by saidtubes and constituting therewith a re arch.

11. In combination, a casing comprising a furnace, two drums disposedone below the other and adjacent an end wall of the casing, a third drumadjacent the other end of the casing, banks of tubes connecting thedrums, a header at the rst mentioned end of the casing, a lower seriesof tubes connecting the header to the lower one of said two drums, anupper series of tubes connecting the header to said lower drum, a wallwithin and extending across the casing adjacent the lower drum, and abaille member extending between said wall and the adjacent end wall ofthe casing, said member being supported by said lower series of tubesand constituting therewith a fire arch.

12. In combination, a casing comprising a furnace, two drums andadjacent an end of the casing, a third drum adjacent the other end ofthe casing, banks of tubes connecting the drums, headers at each end ofthe casing, tubes connecting the respective headers to the drumsadjacent thereto, and tubes connecting the headers and extending overthe combustion space of the furnace.

yASHUiEt U. WETHERBEE.

disposed one below the other.

ist

